select
navigate
switch tabs
Esc close

Draft angles for master model?

0
P
3

hi, I’m designing the master model for a silicone mold (for vacuum casting) and wondering about the necessity of incorporating draft angles. Is it always required to include draft angles in the design, or are there specific cases where the material properties, mold complexity, or part geometry allow for skipping them? These holes in a cutaway detail are a good example, should I draft or not draft? thank you

Solved by Rafael Angulo
They’re only important if the next stage is a plan to go to more rigid, higher production capacity methods. Injection molding demands thorough care with draft angles to enable smooth ejection. Building them saves time for knock-on design changes later. Your model would closely match the final part. For a prototype or one-off design, they’re basically of no value. Silicone molds are so flexible they allow you to focus on part function without worrying about extraction. However, where a part’s geometry has deep or sharp features, adding draft angles might extend the mold's service life by reducing stress.
    • P

      hi, I’m designing the master model for a silicone mold (for vacuum casting) and wondering about the necessity of incorporating draft angles. Is it always required to include draft angles in the design, or are there specific cases where the material properties, mold complexity, or part geometry allow for skipping them? These holes in a cutaway detail are a good example, should I draft or not draft? thank you

      0
    • R

      No, draft angles aren’t strictly necessary when vacuum casting in silicone molds, but they might help in these long draws if you drill to parallel after casting. The flexibility of silicone means it can handle undercuts and intricate geometries without the need for any consideration of draft angles. This makes it easy to create complex shapes that would otherwise need much more complexity/processing in rigid molds.

      0
      Reply
      • P
        Rafael Angulo

        thanks. In what situations would you recommend adding draft angles?

        0
        Reply
      • R
        Pete Read

        They’re only important if the next stage is a plan to go to more rigid, higher production capacity methods. Injection molding demands thorough care with draft angles to enable smooth ejection. Building them saves time for knock-on design changes later. Your model would closely match the final part. For a prototype or one-off design, they’re basically of no value. Silicone molds are so flexible they allow you to focus on part function without worrying about extraction. However, where a part’s geometry has deep or sharp features, adding draft angles might extend the mold’s service life by reducing stress.

        0
        Reply
Draft angles for master model?
Your information:




Suggested Topics

Topic
Replies
Views
Activity
Thermal expansion modelling for a braced rectangular steel tank
hi, for a welded steel coolant reservoir for a test stand - 4 m × 2 m × 1.5 m with internal bracing I need to account for thermal expansion. Fluid runs at 80–90... read more
B
0
80
Dec 22
Designing holes for M3 threaded inserts in an ABS enclosure
Hi! In my design for a small ABS enclosure for an onboard sensor module I want to switch from molded bosses to heat-set M3 inserts for the lid screws. Before I finalize CAD, what... read more
A
o
1
174
Dec 23
Airtight joint between two aluminum frame enclosures?
Hi, I have two 400 mm cubical enclosures from 20×20 mm aluminum profiles with glass on all sides except one. I need to connect them into a single temperature-controlled unit and keep the joint... read more
M
D
F
2
281
Dec 29
How to correctly specify standard and non-standard threads in a technical drawing?
For a machined part that has both standard and non-standard thread types, what’s the best way to call out threads in the technical drawing? In particular, should I use thread callouts or full detail... read more
I
R
6
820
Nov 14
Drawing callout for tight tolerance over short bore length
hi, I have an aluminum housing for a small gearbox where the bearing seats are, of course, critical. I need to hold tight tolerances on the ID and OD, but only over a short... read more
A
S
4
609
Oct 31